Characteristics of materials can be changed by doping or otherwise introducing species into the materials. For example, characteristics of metal alloys can be changed by diffusing substances into the metal alloys, such as by diffusing nitrogen into the surface of a metal to create a case-hardened surface.
Nitrogenation can be used to change the magnetic characteristic of a metal. The metal can be exposed to nitrogen, which incorporates at least some of the nitrogen into the metal. The incorporation of the nitrogen can change the metal from a magnetic material to a non-magnetic material, or a material that is less magnetic than prior to exposure to the nitrogen.
Due to diffusion of nitrogen during the nitrogenation process, it can be difficult to control which areas of the metal are exposed to nitrogen. One approach to controlling which areas of the metal receive nitrogen during the nitrogenation process involves applying a ceramic mask to the metal. Locations having the ceramic mask receive little to no nitrogen and, as a result, maintain the magnetic characteristic that the metal had prior to the nitrogenation process. Locations that do not have the ceramic mask receive nitrogen and lose the magnetic characteristic (e.g., these locations are no longer magnetically attracted to magnets, or are less magnetically attracted to magnets). These locations can no longer be ferritic).
But, this ceramic mask can be difficult to remove. The removal can involve chemical and/or mechanical etching of the mask, which can introduce damage to the underlying material. Additionally, this removal operation adds cost and complexity to the process for creating the material having the magnetic areas and non-magnetic areas.